The purpose of this project is to identify determinants of the adoption of Computerized Tomographic (CT) technology by hospitals and its diffusion among states and health service areas (HSAs). Data from a census of CT scanners carried out by the Office of Technology Assessment of the U.S. Congress and information from other sources will be used to test various types of hypotheses. These include expectations about the likely impact of regulations on (1) the types of hospitals that adopted CT technology; (2) the timing of their adoption; (3) the extent and (4) rate of diffusion among states and HSAs, and, finally, on (5) the extent to which CT scanners were acquired by institutions or persons other than hospitals. Special attention will be given to the possible combined effects of various regulatory programs - "regulatory intensity" - and to the competitiveness of hospitals' environments. Hypotheses will be tested using multivariate techniques and, for the diffusion analyses, mathematical models of the diffusion process. In the multivariate analyses, extraneous factors to be controlled include hospital characteristics and endogenous and exogenous market variables.